FBI spokeswoman Lindsay Ram said FBI and US Capitol Police arrested Awan at Washington's Dulles International Airport as he attempted to travel to Pakistan.
The complaint and affidavit against Awan accused him and his wife, Hina Alvi, of attempting to commit bank fraud by misrepresenting themselves on a loan for a rental property they had and then wiring the proceeds to two unnamed persons in Pakistan.
Christopher Gowen, an attorney for Awan, said Schultz's office fired him after the arrest. David Damron, a spokesman for Wasserman Schultz, confirmed to CNN that Awan had worked in the Florida Democrat's office and had been fired.
Asked if Alvi, who the complaint refers to at length, had been charged, Gowen said, "Not yet."
Awan, 37, of Lorton, Virginia, was a shared employee paid by more than a dozen Democratic House offices, congressional disbursement documents show, for January to March 2017, the most recent period for which data are available.
A report from BuzzFeed
in early February said House staffers were under investigation for stealing equipment, and Politico
reported Awan was one of those under investigation. Gowen said most offices ended their relationship with Awan, but that Wasserman Schultz's office continued to keep him on the payroll until the day of the arrest.
The complaint said that on March 5, Alvi took her three children out of school and went to Dulles International Airport to board a Qatari-bound flight on her way to Pakistan.
At the airport, customs authorities conducted a search of Alvi and the children's luggage and found slightly more than $12,000 in cash. A secondary search turned up cardboard boxes of household items and clothing. They were permitted to board the flight and have not returned to the US since. The FBI declined to offer further details about that day outside of what was in the complaint.
Awan, the complaint said, bought a flight that was headed to Qatar and then Pakistan on July 24. He was arrested at the airport as he attempted to take the flight, which his lawyer said he had purchased weeks prior.
Bill Miller, a spokesman for the US attorney's office in DC, said Awan was arraigned in US District Court on Tuesday and charged with one count of bank fraud. He pleaded not guilty and was released "pursuant to a high-intensity supervision program," Miller said.
Miller said Awan would have a curfew and a GPS monitor and that he could not go more than 50 miles away from his home and had to turn over his passports, according to the conditions of his release.
Gowen said Awan's family was staying with extended family in Pakistan because Awan and Alvi were both fired, and that a spiraling fixation on them from right-wing bloggers had led to harassment. He predicted success for Awan in court.
"This is a truly political thing," Gowen said.
Miller said Awan's preliminary hearing was scheduled for August 21.
CORRECTION: This story has been updated to reflect the day of Awan's arrest.